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Discussion Starter · #21 · (Edited)
Some good comments above from Kruiser, tjm73, and Saleen414. We live in a "Monkee See, Monkey Do" world. We are bombarded with nonsense on TV and on the Internet every day. As someone once said, "if you BS people over and over every day, there comes a time when they believe it". Yes, 1 5/8" primaries are fine for a mild street engine. Almost every single aftermarket cylinder head for the Small Block Ford has a 1.60" diameter exhaust valve. 1.60" is less than 1 5/8" (1.625"). Why would any mild 302 or 351W need a 1 7/8" or 2" header? I define "mild" as bolt-on stuff only, maybe a larger carb or throttle body, headers, etc. Basically a 300 to 350 HP engine. About Shorty Headers, I installed a set 34 years ago on my '87 Mustang. They were 1 5/8" which were somewhat better than the OEM 1 1/2". On the chassis dyno, I picked up zero horsepower, everything else being equal. I took them off and cut off the ball & socket part and welded on a 2 1/2" pipe (or was it a 2 1/4" pipe, I can't remember but it was the same size as the OEM exhaust system). Once I did that, back on the chassis dyno, and just doing that picked up 8 HP. Shortly after, they came out with the so-called "equal length" Shorty Headers. That was a con job, the primaries were NOT all the same length and even if they had been, the super tight radius bends were HP killers. Having daily access to a chassis dyno was a major advantage for me. I removed my OEM mufflers and tail pipes and installed a set of 2-Chamber Flowmaster mufflers. Other than getting a headache from the noise, I could not see any change in the horsepower. I removed the tail pipes again (and for the last time) and installed those little down-turns after the mufflers, and picked up about 4 or 5 HP. Little increments like this proved nothing, they were meaningless. For all I know, a 5 HP change, either up or down, could mean that nothing changed. It could all be just a change in the weather or temperature between 9:00 AM and 3:00 in the afternoon. Once I started making changes to the bolt-on stuff, I did the usual bigger changes, better cylinder heads, bigger camshafts, better intake manifolds, bigger injectors, bigger throttle body, the usual stuff, still nothing radical. It was my everyday street car still, but I went with Chris Kaufmann's "Speedbreeding" plan as outlined in Hot Rod Magazine. It was smooth as silk on the street and running in the mid 12's in the 1/4 mile with 3:73 gears. As far as headers, Gary Hooker (the founder of Hooker Headers) gave me a set of 1 3/4" Long Tubes. They had 3" collectors (and no ball & socket crap) and I used some adapters to fit them on the OEM H-Pipe.
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Eventually, I gutted this car, (removed about 600+ lbs out of it) turned it into an all out drag car with a full cage, and still drove it on the street everyday. We must have tried a dozen different header designs on this car (headers that we built ourselves), always running through the mufflers, Long Tubes and Mid Lengths, in 1 3/4" and 1 7/8", trying many different primary lengths and collector styles. The drag strips were our new "dyno". It turned into a very nice 10 second car that was always fully streetable (although not smog legal in CA) and using pump gasoline. Steve Saleen liked the car, and "made" it into a Saleen for me and painted it white (all at no charge).
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I donated the car to a Police Department in Antioch, IL, and they installed their logo and the light bar on it and raced it in the police car drag races, and used it in anti-drug campaigns...
 

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Wow. And that's why I don't have LT's on my street car. You can't even see my exhaust from the side of the car. Yikes!
Can't see the longtubes on mine from the side either. :D
 

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Silly way to measure, but you CAN see my 3" exhaust (to the mufflers) from the side. Huh, look at that - you can see the OEM size 14" mufflers hanging from the OEM hangars. Next thing you know someone will see my tailpipes. Ooo lala - I'm so embarrassed! :censored:

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Discussion Starter · #24 ·
I think that the bottom line on all of this is that your headers and exhaust system are just another part of "your combination". They have to fit together, with what you have "with the engine", and how you are going to "use" your vehicle. On my '87 LX above, even as an all out race car, we still relied on 1 3/4" primaries when trying out the Long Tubes or the Mid Lengths. The 1 7/8" Long Tubes I tried as an experiment did not make the car go any quicker or faster, although it might have if we used higher flowing cylinder heads and a more radical camshaft, and a higher capacity intake system. Ultimately, the engine is an "air pump", and the more air it flows, the more HP it's going to make, and the more exhaust flowing capacity it is going to need...
 

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As far as headers for street/strip Mustangs, and with the emphases more on street than strip, and especially on the 302 engines (8.2" cylinder blocks), 1 3/4" headers (Long Tube or Mid Length) is more than sufficient. We have customers making 750+ HP using the 1 3/4" headers. On most Small Block Ford engines, the bottle neck is not the primary tube size as much as it is the cylinder head. All of the aftermarket cylinder heads for the SB Ford have 1.60" diameter exhaust valves. 1.60" is smaller around than 1 5/8" (which is 1.625"). But the exhaust does not go through a hole in the exhaust port that is 1.60" in diameter, it goes through the valve seat, which tapers down even smaller (not much larger than 1 1/2") before going out of the port. That's where the bottle neck is regarding exhaust flow. You can grind on the exhaust port all you want, but the "door" to the headers is still only 1.60" in diameter. This is why on a 302 engine, even the ones punched out to 347 cubes or bigger can do just fine using 1 3/4" headers as long as they are GOOD 1 3/4" headers...
I know this is an old thread, but how much would a set of 1-3/4 long tubes with a 2.5 inch collector diameter size run me? Must fit stock E7 heads per NHRA rules…
 

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Discussion Starter · #29 ·
People need to understand, RCI Headers were never a "production" headers company. Each header order was fabricated one at a time, where the deck height, cylinder head, transmission, bell housing, primary size, etc. was taken into consideration. Each header was fabricated by Craig Quinn, the owner of RCI Headers. Taking new orders stopped when Craig was hospitalized with the Covid virus in late December, 2021. Craig never made it out of the hospital and passed away in January, 2022. The entire fabrication process was handled by Craig. Other than Craig, there were no employees at RCI. I was not an employee, I was an outside contractor. I received no salary, only a commission on the header sales. In fact, my office was more than 30 miles from RCI's shop. After Craig's death, his ex-wife took over Craig's assets, and what she did with the equipment in the shop is not known. She has never responded to any of my numerous calls...
 
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